Despite workaholic coaches' best efforts, football has always been an inexact science. This time of year, 2½ weeks before the NFL season, teams have 90 players stretched across multiple fields at practice. For coaches, evaluating all that talent has long been part guesswork.

Until now. Here's what's coming to a practice field near you: data. Lots of it. And football will never be the same.

A handful of technological forces have converged on the NFL this year to create some behind-the-scenes statistical revolutions. This off-season, the NFL struck a deal with Zebra Technologies Corp.ZBRA1.57% to put radio-frequency tracking devices in the shoulder pads of players. The technology will be installed in every stadium that hosts a Thursday Night Football game. But over the past year, teams such as the Detroit Lions and Philadelphia Eagles already have implemented similar technology, from Zebra or another company, Catapult, for their daily practices.

In other training camps, you can find cameras in the helmets of quarterbacks—an attempt to answer the age-old question of what a quarterback is looking at as he tries to make a play.

"We get to test some old theories that have been in place forever," said Lions president Tom Lewand.

For football, which is still a rather old-school sport, this is a Moneyball moment. Actually, it's beyond that: The evidence of a player's worth will come from practice, not just from game statistics and minor-league or amateur performances. It may just be the end of guessing in the NFL.

Previously, data gathered in practice served only to help with "confirmation bias" among talent evaluators, said Kansas City Chiefs general manager John Dorsey. For example, if you had a fast player, you wanted to know how fast he was. There was little exploration of anything deeper than that.

But this is different. Simple, straightforward measurements like speed and calorie count will allow for even the oldest of old-school coaches to digest the information.

"Football is apprehensive to change," Dorsey said. "But this will allow you to blend the old and the new together."

According to Lions offensive coordinator Joe Lombardi, player monitoring will allow coaches to get specific information on virtually anything practice-related—like whether a player is being lazy in practice. "We can get the data and say, 'Hey, you went way harder a couple of day ago, guys, what happened?'" Lombardi said.

Teams are particularly keen on finding out how much joint stress a player is under on a particular play. That will, in turn, determine how sustainable the play is over the course of a game or a practice. If a player's joints are fluid running a curl route, for instance, it could be run indefinitely.

"We will know this guy can take more [plays] because he's not burning as many calories as that guy," Lombardi said.

The result? Coaching will change, myths will be busted about players' tendencies and fans' understanding of the game will improve, since TV broadcasters will have the data during select games. In short, if you think Lions star receiver Calvin Johnson runs faster in the fourth quarter than the second, you are about to find out.

Granted: Football likely will never have the analytics revolution that has occurred in other sports since there are so few games—16 a year, less than a tenth of baseball's 162. But that won't stop talent evaluation, especially at the college level, from getting more evolved.

The big leaps will be in specific measurements, said St. Louis Rams general manager Les Snead. For instance, a quarterback prospect's throwing velocity could be measured. Once there is enough raw data on every quarterback's velocity, teams can figure out how hard a quarterback has to throw to, say, split two safeties or throw behind a linebacker for a first down. The possibilities are endless.

Meanwhile, coaches are salivating over the possibility that every player could soon have a camera in their helmet. How a quarterback "reads" a play before throwing the ball is crucial information, since it reveals whether the play's failure is because of a bad throw or a bad read of the play.

The Pittsburgh Steelers knew this when they experimented with cameras in helmets during summer workouts. "When we tape football, we do it from an end zone, the sideline and a high angle, and none of that is what a player sees," said Steelers general manager Kevin Colbert. "To be able to tell a quarterback where he should be, to be able to show a defense what an offense looks like at ground level would be great. That would be more realistic."

Chicago Bears coach Marc Trestman said he is experimenting with cameras at ground level to get a better perspective over the classic method of shooting practice from high in the sky.

But the helmet camera isn't yet in wide use. The problem, for now, is any camera is too bouncy inside the quick-moving helmets of players. Steelers offensive coordinator Todd Haley said the film gives headaches to anyone who watches for an extended period. It is still valuable enough to tinker with, though, he said.

The best possible practice technology is still a ways off, the Steelers' Colbert said. His idea? A "Madden"-style videogame that acts more like a simulator. Colbert said race-car drivers have the capability to "simulate a track they've never driven on," with precise angles and speed requirements built into a computer program. But in football there is no current way to accurately figure out the best angle to take against an opposing defense with real-life tendencies programmed into an application.

"Then you could simulate teaching methods that [a team] has," Colbert said. "Of course, I just gave away a big secret. Someone is probably going to make billions off this."

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